A blog about the history, current state, and the future of the electric guitar and tube-based amplifier combo and how this de rigueur musical instrument that matured during the Rock N' Roll-era continues to both evolve and refuses to die.

Tuesday, June 7, 2016

Well noted as the first one to extensively use IC op-amps in
its construction, can the Pro Co Rat be considered the first “modern” guitar
distortion pedal due to its reliability and tonal consistency?

By: Ringo Bones

The raison d’être of guitar distortion pedals is to
replicate the pleasing tone of accidentally damaged electric guitar combo amps –
i.e. ripped and torn speaker cone and / or a dislodged vacuum tube, etc. – and thus
the birth of iconic and pioneering guitar distortion pedals of the 1960s like
the Dallas Arbiter Fuzz Face and the Big Muff Pi which primarily uses early
germanium transistors. Despite of their wicked sustain and tone, germanium
transistor based guitar distortion pedals from the 1960s are not well known for
their tonal consistency – especially in live performance / touring situations –
because early germanium transistors were notorious for their wild parameter
drift with ambient temperature changes and thus tonal consistency from start to
finish of a live performance – never mind from the next concert venue to the
next – eludes these great sounding but notoriously unreliable guitar distortion
pedals. Legend has it that the late great Jimi Hendrix once bought 10
individual Dallas Arbiter Fuzz Face pedals and switch between ones that
maintained the most tonal consistency when played live.

The stated problems of early guitar distortion pedals
probably what inspired Pro Co engineers Scott Burnham and Steve Kiraly to
hot-rod existing distortion pedals during the mid 1970s – such as the Dallas
Arbiter Fuzz Face - as suggested by their clients in order to make these units
sound better. But eventually, the two Pro Co engineers discovered the “weaknesses”
of these early guitar distortion pedals and thus paved the way to a better new
and improved guitar distortion pedal.

The original Pro Co Rat was developed in the basement of pro
Co’s Kalamazoo, Michigan facility in 1978. It was notable for its extensive use
of IC op-amps – or integrated circuit operational amplifiers – such as the 8-pin
dual in-line monolithic Motorola LM308 op-amp. The Pro Co “The RAT” in a
nutshell is a distortion pedal with a quite simple circuit that can be broken
down into four simpler blocks – the distortion stage, tone control stage,
output stage and power supply. Given that the basic circuit was based on a public
domain Popular Electronics published design based on an IC op-amp that was
published around 1966 but was, at first, dismissed by serious guitar players
because it’s sustain wasn’t as good as that of germanium transistor based
guitar distortion pedals. But Burnham and Kiraly noticed the tonal consistency
and immunity from temperature drift of the op-amp based distortion circuit and
thus worked on it until they managed to design one with a tone and sustain that
is more on less equal to that of germanium transistor based units.

The IC op-amp based circuitry of “The RAT” inspired a host
of copycat models during the 1980s – especially during the heyday of Hair Metal
bands. And some of them use other op-amps such as the ubiquitous during the
1980s Motorola LM741. The original Dallas Arbiter Fuzz Face and Big Muff Pi
with their original germanium transistor based circuits may be fetching
sky-high second hand prices on eBay these days, but these units can be a pig to
maintain tonal consistency in live concert tour situations, never mid if you’re
a bar-based working musician. Thus, the Pro Co’s “The RAT” and its op-amp based
variants now reign supreme in the loud guitar playing world.